Aplicación de técnicas de interferometría radar satélite al análisis de estabilidad de taludes en zonas mineras

Resum

This research proposes a methodology for slope stability analysis in mining areas, based on the combination of (remote sensing and in situ) monitoring and numerical modeling techniques, applicable at both regional and local scales, and focusing on the application of satellite radar interferometry (InSAR) as the main monitoring technique. The application of the proposed methodology, its ultimate aim being none other than to reduce the risk associated with the possible occurrence of slope failure (or simply the existence of slope instabilities) in mining, facilitates the interpretation of the results obtained with the different techniques applied, and offers different possibilities for their integration, which allows to provide great added value to the raw satellite InSAR data. Furthermore, the methodology can be used to perform both (predictive) analyses of slope instabilities and (retrospective) analyses of slope failures. The work is structured in three sections. The first describes each part of the methodology developed, including a detailed description of the monitoring and modeling techniques needed to apply the proposed workflow. The second one gathers the results obtained in three study areas, selected mainly according to criteria of applicability, typology, complementarity, and availability of information. Finally, the third section summarizes the main conclusions of the research. The methodology consists of four pillars: (i) application of multi-sensor (InSAR techniques, digital photogrammetry techniques or SfM, and differential satellite navigation techniques or DGNSS), multi-platform (satellite, airborne and terrestrial) monitoring techniques, and of data validation techniques (validation of the monitoring results), (ii) application of spatiotemporal data analysis methods (analysis of the monitoring results), (iii) application of numerical modeling techniques (using finite element modeling techniques or FEM), and (iv) application of data integration techniques (integration of the monitoring and modeling results). The second section presents the results obtained by applying the methodology in the three case studies considered: Sierra Minera de Cartagena-La Unión (Murcia), Las Cruces mine (Seville) and El Feixolín mine (Leon). Thus, on the basis of the work conducted at Sierra Minera, this thesis reports for the first time the application of FEM techniques to perform slope stability analysis in mining areas on a regional scale (predictive analysis), as well as the elaboration of slope instability hazard maps by combining InSAR and FEM techniques. In addition, thanks to the study carried out at Las Cruces, this work shows the possibilities offered by the combination of InSAR, SfM and FEM techniques to perform remote analysis (i.e., based exclusively on the exploitation of remote sensing data) of slope failures in open-pit mining areas on a local scale (retrospective analysis). Finally, this study documents for the first time, based on the investigations conducted at El Feixolín, the application of SfM techniques to the monitoring of slope instabilities in mining areas on a local scale (predictive analysis), further highlighting the advantages associated with the adoption, for slope instability risk management, of monitoring programs based on the combination of InSAR and SfM techniques. The proposed methodology has proven to be effective for analyzing, in the investigated case studies, geomorphological features, source areas, mobilized volumes, displacements along the satellite line of sight, aspects on the failure predictability, elevation differences, 3D displacements, conditioning and triggering factors, and failure mechanisms. Although, in all cases, the application of the methodology developed in this thesis has focused on the analysis of slope instabilities and failures in mining areas, it should be noted that this methodology can likewise be used to analyze all types of instabilities and failures affecting natural and man-made slopes.